Effects of Chronic Vardenafil Treatment Persist after End of Treatment in Rats with Acute Arteriogenic Erectile Dysfunction

Abstract

In our previous study, chronic vardenafil treatment improved erectile function soon after the end of the treatment in rats with acute arteriogenic erectile dysfunction (ED). The aim of this study is to evaluate whether the effects of chronic vardenafil treatment persist after the end of treatment using rats with acute arteriogenic ED. Rats were randomly divided into three groups: (i) control; (ii) ligation; and (iii) vardenafil + no treatment. Rats in the ligation and vardenafil + no treatment groups underwent ligature of the bilateral internal iliac arteries to induce acute arteriogenic ED and were subsequently treated with vehicle or vardenafil (4.0 mg/kg/day), respectively, for 3 weeks. Subsequently, all rats were kept for a further 2 weeks with no treatment. Rats in the control group underwent sham surgery. Erectile function was assessed by changes in intracavernous pressure (ICP). Smooth muscle (SM)/collagen ratios in corpus cavernosum were analyzed by Masson trichrome staining. Transforming growth factor-β1 (TGF-β1 ) mRNA and protein levels in corpus cavernosum (CC) were, respectively, evaluated by real-time polymerase chain reaction (PCR) analysis and Western blotting analysis. ICP/mean arterial pressure (MAP) in the ligation group remained significantly lower than that in control group (P < 0.01). Despite no treatment for 2 weeks, ICP/MAP in the var + no treatment group remained significantly higher than that in ligation group (P < 0.05). SM/collagen ratio in the ligation group remained significantly lower when compared with the control group (P < 0.01). The ratio in the var + no treatment group remained significantly higher when compared with the ligation group at 2 weeks after the end of treatment (P < 0.05). TGF-β(1) mRNA and protein levels did not differ among the groups. The effects of chronic vardenafil treatment on erectile function and penile structure persist, even after the end of treatment, in acute arteriogenic ED rats.